Do switch mode power supplies flicker in time with mains? Specifically LED power supplies in commercially available domestic lamps. By in time, I don't mean at the same 50/60Hz, but anchored to it. I.e. if you have several such lamps each with their own built in supply, will they all flicker in time, using the mains frequency to keep them in time, or will they be random, making the room overall not flicker due to them all being random? And is there any way I can test this? I tried taking photos of them, but my camera only goes as fast as 1/2000th of a second, which shows all the lights at the same brightness each time, I suspect the flicker is above 2000Hz.

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Specifically LED power supplies in commercially available domestic lamps.

None of mine flicker at all.

By in time, I don't mean at the same 50/60Hz, but anchored to it. I.e. if
you have several such lamps each with their own built in supply, will they
all flicker in time, using the mains frequency to keep them in time, or
will they be random, making the room overall not flicker due to them all
being random?

None of mine flicker at all.

And is there any way I can test this?

Yes, Get or make a strobe disk or use
one of the original LP disks that has
a strobe disk on it and see what it looks
like with the lights illuminating it. You'll
get it appearing to freeze when rotating
if the light level is varying in synch with
the mains frequency.

I tried taking photos of them, but my camera only goes as fast as 1/2000th
of a second, which shows all the lights at the same brightness each time,
I suspect the flicker is above 2000Hz.

Or they don't flicker at all. No reason why a proper
switched mode power supply needs to have any
AC component at all on its output. The cruder
ones may well do.

They probably are fairly crude. I know they flicker, for example if I use my cordless drill, the chuck appears to spin the wrong way under the LED lighting.

But it's nothing like as low as 50Hz. What I want to know is if the higher frequency they're flickering at is anchored with the rise of the AC wave. I.e. will all the LED lights in the room flicker at precisely the same time, or will they be out of synch (due to tolerances in the circuitry of each PSU) and fudge the brightness together.

Rod SpeedGuest

Wed Dec 19, 2018 1:45 pm

William Gothberg <"William Gothberg"@internet.co.is> wrote

> Do switch mode power supplies flicker in time with mains?

No.

> Specifically LED power supplies in commercially available domestic lamps.

None of mine flicker at all.

Quote:

By in time, I don't mean at the same 50/60Hz, but anchored to it. I.e. if
you have several such lamps each with their own built in supply, will they
all flicker in time, using the mains frequency to keep them in time, or
will they be random, making the room overall not flicker due to them all
being random?

None of mine flicker at all.

> And is there any way I can test this?

Yes, Get or make a strobe disk or use
one of the original LP disks that has
a strobe disk on it and see what it looks
like with the lights illuminating it. You'll
get it appearing to freeze when rotating
if the light level is varying in synch with
the mains frequency.

Quote:

I tried taking photos of them, but my camera only goes as fast as 1/2000th
of a second, which shows all the lights at the same brightness each time,
I suspect the flicker is above 2000Hz.

Or they don't flicker at all. No reason why a proper
switched mode power supply needs to have any
AC component at all on its output. The cruder
ones may well do.

Specifically LED power supplies in commercially available domestic
lamps.

None of mine flicker at all.

By in time, I don't mean at the same 50/60Hz, but anchored to it. I.e.
if
you have several such lamps each with their own built in supply, will
they
all flicker in time, using the mains frequency to keep them in time, or
will they be random, making the room overall not flicker due to them all
being random?

None of mine flicker at all.

And is there any way I can test this?

Yes, Get or make a strobe disk or use
one of the original LP disks that has
a strobe disk on it and see what it looks
like with the lights illuminating it. You'll
get it appearing to freeze when rotating
if the light level is varying in synch with
the mains frequency.

I tried taking photos of them, but my camera only goes as fast as
1/2000th
of a second, which shows all the lights at the same brightness each
time,
I suspect the flicker is above 2000Hz.

Or they don't flicker at all. No reason why a proper
switched mode power supply needs to have any
AC component at all on its output. The cruder
ones may well do.

They probably are fairly crude. I know they flicker, for example if I use
my cordless drill, the chuck appears to spin the wrong way under the LED
lighting.

But it's nothing like as low as 50Hz. What I want to know is if the
higher frequency they're flickering at is anchored with the rise of the AC
wave.

No its not.

Quote:

I.e. will all the LED lights in the room flicker at precisely the same
time, or will they be out of synch (due to tolerances in the circuitry of
each PSU)

Due to it not being synched with the mains, actually.

> and fudge the brightness together.

Its not a fudge, it's the lack of synch.

And you should be able to see that by watching
the chuck as you move the drill between lights.
The rate and direction of rotation should change.

Specifically LED power supplies in commercially available domestic
lamps.

None of mine flicker at all.

By in time, I don't mean at the same 50/60Hz, but anchored to it. I.e.
if
you have several such lamps each with their own built in supply, will
they
all flicker in time, using the mains frequency to keep them in time, or
will they be random, making the room overall not flicker due to them all
being random?

None of mine flicker at all.

And is there any way I can test this?

Yes, Get or make a strobe disk or use
one of the original LP disks that has
a strobe disk on it and see what it looks
like with the lights illuminating it. You'll
get it appearing to freeze when rotating
if the light level is varying in synch with
the mains frequency.

I tried taking photos of them, but my camera only goes as fast as
1/2000th
of a second, which shows all the lights at the same brightness each
time,
I suspect the flicker is above 2000Hz.

Or they don't flicker at all. No reason why a proper
switched mode power supply needs to have any
AC component at all on its output. The cruder
ones may well do.

They probably are fairly crude. I know they flicker, for example if I use
my cordless drill, the chuck appears to spin the wrong way under the LED
lighting.

But it's nothing like as low as 50Hz. What I want to know is if the
higher frequency they're flickering at is anchored with the rise of the AC
wave.

No its not.

I.e. will all the LED lights in the room flicker at precisely the same
time, or will they be out of synch (due to tolerances in the circuitry of
each PSU)

Due to it not being synched with the mains, actually.

I meant if the PSUs were absolutely identical, and all the lights were switched on at the same time (with one lightswitch), they should remain in synch forever. But since there are tolerances in all the components in the PSUs, they won't stay in time.

Quote:

and fudge the brightness together.

Its not a fudge, it's the lack of synch.

I didn't mean fudge, I meant smudge.

Quote:

And you should be able to see that by watching
the chuck as you move the drill between lights.
The rate and direction of rotation should change.

Only if the frequency is different, which I doubt as they are all the same model. What I need is a way of detecting if they're flashing together.

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that made stinky shit, but then why does vegetarian human shit stink? Is it
just the fact that we're capable of digesting meat?"

Senile Rot: "Nope, some cow shit stinks too."

Message-ID: <fv5f1tFi3f2U1_at_mid.individual.net>

Mark LloydGuest

Wed Dec 19, 2018 5:45 pm

On 12/19/18 5:23 AM, William Gothberg wrote:

Quote:

Do switch mode power supplies flicker in time with mains? Specifically
LED power supplies in commercially available domestic lamps. By in
time, I don't mean at the same 50/60Hz, but anchored to it. I.e. if you
have several such lamps each with their own built in supply, will they
all flicker in time, using the mains frequency to keep them in time, or
will they be random, making the room overall not flicker due to them all
being random? And is there any way I can test this? I tried taking
photos of them, but my camera only goes as fast as 1/2000th of a second,
which shows all the lights at the same brightness each time, I suspect
the flicker is above 2000Hz.

I once had an audio amplifier with a solar cell rather than a microphone
for the input transducer. This made it possible to listen to light. The
sun is steady, incandescent lights (AC powered) hum.

"Do not thank God for what man does." [Lemuel K. Washburn, _Is The Bible
Worth Reading And Other Essays_, 1911]

Mark LloydGuest

Wed Dec 19, 2018 5:45 pm

On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

Quote:

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under the
LED lighting.

I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under the
LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.

It looks absolutely ridiculous with modern cars with LED headlights in films. How hard can it be to put a smoothing capacitor on the output of the power supply?

On 12/19/18 5:23 AM, William Gothberg wrote:
Do switch mode power supplies flicker in time with mains? Specifically
LED power supplies in commercially available domestic lamps. By in
time, I don't mean at the same 50/60Hz, but anchored to it. I.e. if you
have several such lamps each with their own built in supply, will they
all flicker in time, using the mains frequency to keep them in time, or
will they be random, making the room overall not flicker due to them all
being random? And is there any way I can test this? I tried taking
photos of them, but my camera only goes as fast as 1/2000th of a second,
which shows all the lights at the same brightness each time, I suspect
the flicker is above 2000Hz.

I once had an audio amplifier with a solar cell rather than a microphone
for the input transducer. This made it possible to listen to light. The
sun is steady, incandescent lights (AC powered) hum.

That was 40 years ago. Maybe something like that would work today.

The trouble is I want to compare 2kHz+ from one light with 2kHz+ from a neighbouring light and see if they're in sync.

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under the
LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.

You can also observe such things using a smartphone that has a high FPS rate for recodring movie.
I can see the labs lights flicker when I film at 240FPS standard 60 and everything seems fine.

Everybody seems to constantly cut corners. Lights should just be on, no flicker at all. Fucking annoying if you have decent eyesight, I can see the flicker from almost everyone's LED tail lights.